Diabetes is a chronic disorder affecting carbohydrate, fat and protein metabolism in animals.
Type I diabetes mellitus, which comprises approximately 10% of all diabetes cases, was previously referred to as insulin-dependent diabetes mellitus (“IDDM”) or juvenile-onset diabetes. This disease is characterized by a progressive loss of insulin secretory function by beta cells of the pancreas. This characteristic is also shared by non-idiopathic, or “secondary,” diabetes having its origins in pancreatic disease. Type I diabetes mellitus is associated with the following clinical signs or symptoms: persistently elevated plasma glucose concentration or hyperglycemia; polyuria; polydipsia and/or hyperphagia; chronic microvascular complications such as retinopathy, nephropathy and neuropathy; and macrovascular complications such as hyperlipidemia and hypertension which can lead to blindness, end-stage renal disease, limb amputation and myocardial infarction.
Type II diabetes mellitus (non-insulin-dependent diabetes mellitus or NIDDM) is a metabolic disorder involving the dysregulation of glucose metabolism and impaired insulin sensitivity. Type II diabetes mellitus usually develops in adulthood and is associated with the body's inability to utilize or make sufficient insulin. In addition to the insulin resistance observed in the target tissues, patients suffering from type II diabetes mellitus have a relative insulin deficiency—that is, patients have lower than predicted insulin levels for a given plasma glucose concentration. Type II diabetes mellitus is characterized by the following clinical signs or symptoms: persistently elevated plasma glucose concentration or hyperglycemia; polyuria; polydipsia and/or hyperphagia; chronic microvascular complications such as retinopathy, nephropathy and neuropathy; and macrovascular complications such as hyperlipidemia and hypertension which can lead to blindness, end-stage renal disease, limb amputation and myocardial infarction.
Dyslipidemia, or dislipidemia, includes lipoprotein overproduction or deficiency; sometimes associated with diabetes, it is a common cause of lipidemia. For example, it is recommended for adults with diabetes to have their levels of LDL, HDL, total cholesterol, and triglyceride measured regularly. The desirable levels for such adults can be: LDL—less than 100 mg/dL (2.60 mmol/L), HDL—no less than 40 mg/dL (1.02 mmol/L), and triglyceride—less than 150 mg/dL (1.7 mmol/L). When blood cholesterol is too high, the condition is referred to as hypercholesterolemia. In one instance, dyslipidemia can include hypertriglyceridemia, and mixed hyperlipidemia. In terms of the above indices, dyslipidemia (including hyperlipidemia) may be one or more of the following conditions: low HDL (<35 or 40 mg/dl), high triglycerides (>200 mg/dl), and high LDL (>150 mg/dl).
Compounds having retinoid-like activity are useful for preventing, treating or at least alleviating the symptoms and conditions of numerous diseases and conditions. There are two main types of retinoid receptors: the Retinoid X Receptors (RXRs) including their subtypes RXRα, β, γ, and the Retinoic Acid Receptors (RARs), also including their subtypes RARα, β, γ. Retinoid receptor modulators are useful in a variety of conditions including, but not limited to, metabolic disorders, such as type II diabetes, dyslipidemia, hypercholesterolemia, and atherosclerosis, and various cancerous and precancerous conditions in the breast, skin, prostate, cervix, uterus, colon, bladder, esophagus, stomach, lung, larynx, oral cavity, blood and/or lymphatic systems. For example, RXRs belong to the nuclear receptor superfamily and consist of a large number of ligand-regulated transcription factors that mediate the diverse physiological functions of steroid hormones, retinoids, thyroid hormone, and vitamin D in embryonic development, growth, differentiation, apoptosis, and homeostasis (Mangelsdorf, D. J., et al., Cell 83, 841-850 (1995); Kastner, P., et al., Cell 83, 859-869 (1995)).
RXR modulators have been identified as insulin sensitizing drugs. All diabetics, regardless of their genetic and environmental backgrounds, have in common an apparent lack of insulin or inadequate insulin function. Because transfer of glucose from the blood into muscle and fatty tissue is insulin dependent, diabetics lack the ability to utilize glucose adequately, which leads to undesired accumulation of glucose in the blood, or hyperglycemia. Chronic hyperglycemia leads to decrease in insulin secretion and contributes to increased insulin resistance, and as a result, the blood glucose concentration is increased so that diabetes is self-exacerbated (Diabetologia, 1985, “Hyperglycaemia as an inducer as well as a consequence of impaired isle cell function and insulin resistance: implications for the management of diabetes”, Vol. 28, p. 119); Diabetes Cares, 1990, Vol. 13, No. 6, “Glucose Toxicity”, pp. 610-630). Therefore, by treating hyperglycemia, the aforementioned self-exacerbating cycle can be interrupted so that prophylaxis or treatment of diabetes is made possible.
U.S. Pat. No. 6,048,873 to Vasudevan et al. is directed to novel compounds having retinoid-like biological activity. More specifically, it is directed to compounds that include a substituted tetrahydroquinoline moiety and a 2,4-pentadienoic acid moiety and have selective activity for retinoid X receptors.
U.S. Pat. No. 5,739,338 to Beard et al. is directed to novel compounds having retinoid antagonist and/or retinoid inverse-agonist-like biological activity. More specifically, it is directed to aryl substituted tetrahydroquinoline derivatives which bind to retinoid receptors and have retinoid-like, retinoid antagonist or retinoid inverse agonist-like biological activity.
There is a continuing need for new RXR agonists. There is also a need for RXR agonists useful for the treatment of conditions including but not limited to cancer and metabolic disorders such as diabetes, dyslipidemia, and hypercholesterolemia.